1. Field of the Invention
The present invention relates to an optical apparatus using an optical system such as an optical element, a microscope, a lithographic optical system, or an optical system of an optical disk.
2. Description of the Related Art
Conventionally, in the above optical system, a water-immersion method, oil-immersion method, or solid immersion method has been used to increase an object-side numerical aperture in order to increase resolution (see non-patent document 1 listed below). Further, there are documents as listed below about materials (e.g., photonic crystal) possessing refractive characteristics different from those of a general glass lens and the like (non-patent documents 2 and 3, patent document 1, 2, 3, 4, and 5).
Non-Patent Document 1:
Structure and Application of Optical System P73-77, P166-170, Optronics Co., Ltd., Published on Nov. 19, 2003
Non-Patent Document 2:
J. B. Pendry Phys. Rev. Lett., Vol. 85, 18 (2000) 3966-3969
Non-Patent Document 3:
M. Notomi. Phy. Rev. B. Vol. 62 (2000) 10696
Non-Patent Document 4:
V. G. Veselago Sov. Phys. Usp. Vol. 10, 509-514(1968)
Non-Patent Document 5:
L. Liu and S. He Optics Express Vol. 12 No. 20 4835-4840 (2004)
Non-Patent Document 6:
Sato and Kawakami, Optronics, July issue 2001, P197, published by Optronics Co., Ltd.
Patent Document 1:
U.S. 2003/0227415 A1
Patent Document 2:
U.S. 2002/0175693 A1
Patent Document 3:
Japanese Unexamined Published Patent Application No. 2003-195002
Patent Document 4:
Japanese Unexamined Published Patent Application No. 2004-133040
Patent Document 5:
U.S. 2005/0007567 A1